CVE-2021-45098

moderate-risk
Published 2021-12-16

An issue was discovered in Suricata before 6.0.4. It is possible to bypass/evade any HTTP-based signature by faking an RST TCP packet with random TCP options of the md5header from the client side. After the three-way handshake, it's possible to inject an RST ACK with a random TCP md5header option. Then, the client can send an HTTP GET request with a forbidden URL. The server will ignore the RST ACK and send the response HTTP packet for the client's request. These packets will not trigger a Suricata reject action.

Do I need to act?

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0.65% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (4)

Affected Vendors

Debian Oisf

References (9)

Release Notes https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942
Patch https://github.com/OISF/suricata/commit/50e2b973eeec7172991bf8f544ab06fb782b97df
Release Notes https://github.com/OISF/suricata/releases
Exploit https://redmine.openinfosecfoundation.org/issues/4710
Release Notes https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942
Patch https://github.com/OISF/suricata/commit/50e2b973eeec7172991bf8f544ab06fb782b97df
Release Notes https://github.com/OISF/suricata/releases
https://lists.debian.org/debian-lts-announce/2025/03/msg00029.html
Exploit https://redmine.openinfosecfoundation.org/issues/4710
38
/ 100
moderate-risk
Severity 26/34 · High
Exploitability 2/34 · Minimal
Exposure 10/34 · Low